DPPH radical scavenging and nitric oxide inhibitory activities of the constituents from the wood of Taxus yunnanensis

Antinociceptive activity of doliroside B

CONTEXT

Dolichos trilobus Linn (Leguminosae) is often used in Yi ethnic medicine to treat pain, fracture, and rheumatism.

OBJECTIVE

To explore the therapeutic potential of doliroside B (DB) from D. trilobus and its disodium salt (DBDS) and the underlying mechanism in pain.

MATERIALS AND METHODS

In the writhing test, Kunming mice were orally treated with DB and DBDS at doses of 0.31, 0.62, 1.25, 2.5, and 5 mg/kg. Vehicle, morphine, indomethacin, and acetylsalicylic acid were used as negative and positive control on the nociception-induced models, respectively. In the hot plate test, mice were orally treated with DB and DBDS at doses of 2.5, 5, 10, and 20 mg/kg. In the formalin test, mice were orally treated with DB and DBDS at doses of 2.5, 5, 10, and 20 mg/kg. In the meanwhile, lipopolysaccharide-induced inflammatory model in RAW264.7 macrophages was adopted to study the mechanism of pain alleviation for DBDS.

RESULTS

DBDS (5 mg/kg) inhibited the writhing number by 80.2%, which exhibited the highest antinociceptive activity in pain models. DBDS could selectively inhibite the activity of COX-1. Meanwhile, it also reduced the production of NO, iNOS, and IL-6 by 55.8%, 69.0%, and 49.9% inhibition, respectively. It was found that DBDS also positively modulated the function of GABAA1 receptor.

DISCUSSION AND CONCLUSIONS

DBDS displayed antinociceptive activity by acting on both the peripheral and central nervous systems, which may act on multitargets. Further work is warranted for developing DBDS into a potential drug for the treatment of pain.

Triterpenoid saponins from Psammosilene tunicoides and their antinociceptive activities

Herein, five undescribed oleanane-type triterpenoid saponins, namely, psammosaponins A-E, along with nine known compounds, were isolated from the roots of Psammosilene tunicoides. Moreover, part of the ethanolic extract of P. tunicoides was acid-hydrolyzed and three aglycones were isolated from the resulting hydrolysate. The structures of all compounds were established through extensive analysis involving 1D and 2D NMR experiments, HRESIMS measurements, chemical derivatization, and comparison of spectroscopic data with the values reported in the literature. In all, 10 of the isolated saponins and the three aglycones were evaluated in the acetic acid-induced writhing model for their antinociceptive activity. At a dose of 40 mg/kg, these compounds exhibited significant inhibitory effects on the mouse writhing response, with inhibitions ranging from 31.9% to 79.3%. In addition, the structure-activity relationships of the isolates were discussed. Among the isolates, quillaic acid 3-O-glucuronide and 16α-hydroxygypsogenic acid showed better antinociceptive activity with inhibitions of 79.3% and 73.7%, respectively. Both isolates also exhibited antinociceptive activities in hot plate and formalin tests on mice. Their antinociceptive mechanism was explored in lipopolysaccharide-stimulated RAW 264.7 cells. These isolates could significantly inhibit the production of nitric oxide and interleukin-6 and downregulate the expression levels of inducible NO synthase, COX-1, and COX-2.

PARP deficiency causes hypersensitivity to Taxol through oxidative stress induced DNA damage

Taxol is an antitumor drug derived from the bark of the Pacific Yew tree that inhibits microtubule disassembly, resulting in cell cycle arrest in late G2 and M phases. Additionally, Taxol increases cellular oxidative stress by generating reactive oxygen species. We hypothesized that the inhibition of specific DNA repair machinery/mechanisms would increase cellular sensitivity to the oxidative stress capacity of Taxol. Initial screening using Chinese hamster ovary (CHO) cell lines demonstrated that base excision repair deficiency, especially PARP deficiency, caused cellular Taxol hypersensitivity. Taxane diterpenes-containing Taxus yunnanensis extract also showed hypertoxicity in PARP deficient cells, which was consistent with other microtubule inhibitors like colcemid, vinblastine, and vincristine. Acute exposure of 50 nM Taxol treatment induced both significant cytotoxicity and M-phase arrest in PARP deficient cells, but caused neither significant cytotoxicity nor late G2-M cell cycle arrest in wild type cells. Acute exposure of 50 nM Taxol treatment induced oxidative stress and DNA damage. The antioxidant Ascorbic acid 2 glucoside partially reduced the cytotoxicity of Taxol in PARP deficient cell lines. Finally, the PARP inhibitor Olaparib increased cytotoxicity of Taxol in wild type CHO cells and two human cancer cell lines. Our study clearly demonstrates that cytotoxicity of Taxol would be enhanced by inhibiting PARP function as an enzyme implicated in DNA repair for oxidative stress.

Anti-Inflammatory Activity of Oxyresveratrol Tetraacetate, an Ester Prodrug of Oxyresveratrol, on Lipopolysaccharide-Stimulated RAW264.7 Macrophage Cells

Oxyresveratrol (OXY) has been reported for its anti-inflammatory activity; however, the pharmaceutical applications of this compound are limited by its physicochemical properties and poor pharmacokinetic profiles. The use of an ester prodrug is a promising strategy to overcome these obstacles. In previous researches, several carboxylate esters of OXY were synthesized and oxyresveratrol tetraacetate (OXY-TAc) was reported to possess anti-melanogenic and anti-skin-aging properties. In this study, in addition to OXY-TAc, two novel ester prodrugs of OXY, oxyresveratrol tetrapropionate (OXY-TPr), and oxyresveratrol tetrabutyrate (OXY-TBu), were synthesized. Results from the Caco-2-permeation assay suggested that synthesized ester prodrugs can improve the membrane-permeation ability of OXY. The OXY-TAc exhibited the most significant profile, then this prodrug was chosen to observe anti-inflammatory activities with lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Our results showed that OXY-Tac significantly alleviated secretion of several pro-inflammatory mediators (nitric oxide (NO), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α)), mitigated expression of enzyme-regulated inflammation (inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2)), and suppressed the MAPK cascades. Interestingly, the observed anti-inflammatory activities of OXY-TAc were more remarkable than those of its parent compound OXY. Taken together, we demonstrated that OXY-TAc improved physicochemical and pharmacokinetic profiles and enhanced the pharmacological effects of OXY. Hence, the results in the present study would strongly support the clinical utilities of OXY-TAc for the treatment of inflammation-related disorders.

Lignans as Pharmacological Agents in Disorders Related to Oxidative Stress and Inflammation: Chemical Synthesis Approaches and Biological Activities

Plant lignans exhibit a wide range of biological activities, which makes them the research objects of potential use as therapeutic agents. They provide diverse naturally-occurring pharmacophores and are available for production by chemical synthesis. A large amount of accumulated data indicates that lignans of different structural groups are apt to demonstrate both anti-inflammatory and antioxidant effects, in many cases, simultaneously. In this review, we summarize the comprehensive knowledge about lignan use as a bioactive agent in disorders associated with oxidative stress and inflammation, pharmacological effects in vitro and in vivo, molecular mechanisms underlying these effects, and chemical synthesis approaches. This article provides an up-to-date overview of the current data in this area, available in PubMed, Scopus, and Web of Science databases, screened from 2000 to 2022.

Paclitaxel-Containing Extract Exerts Anti-Cancer Activity through Oral Administration in A549-Xenografted BALB/C Nude Mice: Synergistic Effect between Paclitaxel and Flavonoids or Lignoids

Taxus yunnanensis is a paclitaxel-containing herb with traditional usage in cancer treatment, and its extract possesses great oral bioavailability of paclitaxel. However, it is elusive whether paclitaxel-containing extract (HDS-1) can exert anti-tumor effect through oral administration and how other components contribute to its efficacy. Therefore, we investigate the oral-route anti-tumor effect of HDS-1 in A549-bearing mice. HDS-1-derived flavonoids (HDS-2) and lignoids (HDS-3) are hypothesized to contribute to HDS-1’s efficacy, and their effects of enhancing enterocytic absorption and cytotoxicity of paclitaxel are validated in 2 permeability experiments and apoptosis-related assay, respectively. In vivo, A549 growth is significantly inhibited by 86.1 ± 12.94% ( $P<0.01$ ) at 600 mg/kg of HDS-1 and 65.7 ± 38.71% ( $P<0.01$ ) at 200 mg/kg. HDS-2 and HDS-3 significantly reduce the efflux ratio of paclitaxel to 2.33 and 3.70, respectively, in Caco-2 permeability experiment and reduce paclitaxel reflux in MDCK-MDR1 experiment. Furthermore, HDS-2 and HDS-3 potentiated paclitaxel-induced cytotoxicity by 19.1–22.45% ( $P<0.05$ ) and 10.52–18.03% ( $P<0.05$ ), respectively, inhibited the expression of cyclinB1, Bcl-2, and pMCL-1, and increased the percentage of necrosis cell in the condition of paclitaxel exposure. Conclusively, paclitaxel-containing extracts exert anti-cancer effects through oral administration, and flavonoid and lignoids contribute to its anti-cancer effect through simultaneously improving enterocytic absorption of paclitaxel and the cytotoxic effect of paclitaxel.

Protective Role of Natural Products in Glioblastoma Multiforme: A Focus on Nitric Oxide Pathway

In spite of therapeutic modalities such as surgical resection, chemotherapy, and radiotherapy, Glioblastoma Multiforme (GBM) remains an incurable fatal disease. This necessitates further therapeutic options that could enhance the efficacy of existing modalities. Nitric Oxide (NO), a short-lived small molecule, has been revealed to play a crucial role in the pathophysiology of GBM. Several studies have demonstrated that NO is involved in apoptosis, metastasis, cellular proliferation, angiogenesis, invasion, and many other processes implicated in GBM pathobiology. Herein, we elaborate on the role of NO as a therapeutic target in GBM and discuss some natural products affecting the NO signaling pathway.

The complete chloroplast genome sequence of Taxus yunnanensis

The first complete chloroplast genome (cpDNA) sequence of Taxus yunnanensis was determined from Illumina HiSeq pair-end sequencing data in this study. The cpDNA is 129,190 bp in length. Like other species of taxus genus, the chloroplast genome of T. yunnanensis has lost one of the large inverted repeats (IRs). The genome contains 116 genes, including 82 protein-coding genes, 4 ribosomal RNA genes, and 30 transfer RNA genes. Further phylogenomic analysis showed that T. yunnanensis closed to T. brevifolia in Lauraceae family.

Tissue-specific study across the stem of Taxus media identifies a phloem-specific TmMYB3 involved in the transcriptional regulation of paclitaxel biosynthesis

Taxus stem barks can be used for extraction of paclitaxel. However, the composition of taxoids across the whole stem and the stem tissue-specificity of paclitaxel biosynthesis-related enzymes remain largely unknown. We used cultivated Taxus media trees for analyses of the chemical composition and protein of major stem tissues by an integrated metabolomic and proteomic approach, and the role of TmMYB3 in paclitaxel biosynthesis was investigated. The metabolomic landscape analysis showed differences in stem tissue-specific accumulation of metabolites. Phytochemical analysis revealed that there is high accumulation of paclitaxel in the phloem. Ten key enzymes involved in paclitaxel biosynthesis were identified, most of which are predominantly produced in the phloem. The full-length sequence of TmMYB3 and partial promoter sequences of five paclitaxel biosynthesis-related genes were isolated. Several MYB recognition elements were found in the promoters of TBT, DBTNBT and TS. Further in vitro and in vivo investigations indicated that TmMYB3 is involved in paclitaxel biosynthesis by activating the expression of TBT and TS. Differences in the taxoid composition of different stem tissues suggest that the whole stem of T. media has potential for biotechnological applications. Phloem-specific TmMYB3 plays a role in the transcriptional regulation of paclitaxel biosynthesis, and may explain the phloem-specific accumulation of paclitaxel.

The Lignan Pinoresinol Induces Nuclear Translocation of DAF-16 in Caenorhabditis elegans but has No Effect on Life Span

The lignan pinoresinol is a constituent of flaxseed, sesame seeds and olive oil. Because of different molecular effects reported for this compound, e.g. antioxidative activity, pinoresinol is suggested to cause positive effects on humans. Because experimental data are limited, we have analysed the effects of the lignan on the nematode Caenorhabditis elegans: in spite of a strong antioxidative capacity detected in an in vitro assay, no antioxidative effects were detectable in vivo. In analogy to this result, no modulation of the sensitivity against thermal stress was detectable. However, incubation with pinoresinol caused an enhanced nuclear accumulation of the transcription factor DAF-16 (insulin/IGF-like signalling pathway). Using a strain with an enhanced oxidative stress level (mev-1 mutant), we clearly see an increase in stress resistance caused by this lignan, but no change in reactive oxygen species. Furthermore, we investigated the effects of pinoresinol on the life span of the nematode, but no modulation was found, neither in wild-type nor in mev-1 mutant nematodes. These results suggest that pinoresinol may exert pharmacologically interesting effects via modulation of the insulin-like signalling pathway in C. elegans as well as in other species like mammals due to the evolutionary conservation of this signalling pathway.

Antiproliferative activity of yatein isolated from Austrocedrus chilensis against murine myeloma cells: cytological studies and chemical investigations

CONTEXT

Fitzroya cupressoides (Molina) I. M. Johnst. and Austrocedrus chilensis (D. Don) Pic.Serm. & Bizzarri are two Chilean Cupressaceae that are naturally resistant to biodegradation. Secondary metabolites from these species display a variety of biological activities.

OBJECTIVE

To evaluate the antiproliferative activity of two lignans, a diterpene and a flavonol isolated from A. chilensis and F. cupressoides, to elucidate their cytological effects on P3X murine myeloma cells.

MATERIALS AND METHODS

The antiproliferative activity of yatein, isotaxiresinol, ferruginol, and isorhamnetin was evaluated in vitro using the MTT assay. The effect of yatein at the cellular level, due to its high antiproliferative activity was evaluated. P3X cells treated for 24 h with 12.5 and 25 µg/mL of yatein were also examined at the cytological level using immunofluorescence and scanning and transmission electron microscopy.

RESULTS

Yatein, a lignan isolated from A. chilensis, potentially inhibited P3X murine myeloma cell proliferation, resulting in approximately 75% cell death in response to a 25 µg/mL treatment with the lignan. P3X cells lost membrane integrity at the nuclear and cytoplasmic levels, including organelles, in response to yatein treatment (12.5 µg/mL), and we observed changes in the cytoplasmic organization and distribution of microtubules. The other compounds tested had low activity.

DISCUSSION AND CONCLUSIONS

Yatein is a lignan precursor of podophyllotoxin, a key agent in anticancer drugs. Due to its structural similarities to podophyllotoxin, yatein could have similar cytoplasmic target(s), such as the microtubular apparatus. These findings suggest that yatein may be of potential pharmacological interest and warrants further investigation in human cell lines.

Anti-inflammatory and anti-cancer activity of mulberry (Morus alba L.) root bark

Background

Root bark of mulberry (Morus alba L.) has been used in herbal medicine as anti-phlogistic, liver protective, kidney protective, hypotensive, diuretic, anti-cough and analgesic agent. However, the anti-cancer activity and the potential anti-cancer mechanisms of mulberry root bark have not been elucidated. We performed in vitro study to investigate whether mulberry root bark extract (MRBE) shows anti-inflammatory and anti-cancer activity.

Methods

In anti-inflammatory activity, NO was measured using the griess method. iNOS and proteins regulating NF-κB and ERK1/2 signaling were analyzed by Western blot. In anti-cancer activity, cell growth was measured by MTT assay. Cleaved PARP, ATF3 and cyclin D1 were analyzed by Western blot.

Results

In anti-inflammatory effect, MRBE blocked NO production via suppressing iNOS over-expression in LPS-stimulated RAW264.7 cells. In addition, MRBE inhibited NF-κB activation through p65 nuclear translocation via blocking IκB-α degradation and ERK1/2 activation via its hyper-phosphorylation. In anti-cancer activity, MRBE deos-dependently induced cell growth arrest and apoptosis in human colorectal cancer cells, SW480. MRBE treatment to SW480 cells activated ATF3 expression and down-regulated cyclin D1 level. We also observed that MRBE-induced ATF3 expression was dependent on ROS and GSK3β. Moreover, MRBE-induced cyclin D1 down-regulation was mediated from cyclin D1 proteasomal degradation, which was dependent on ROS.

Conclusions

These findings suggest that mulberry root bark exerts anti-inflammatory and anti-cancer activity.

Inhibition of nitric oxide production in lipopolysaccharide-activated RAW264.7 macrophages by isolated xanthones from the roots of Cratoxylum formosum ssp. pruniflorum

The inhibitory activity of extract and compounds isolated from the roots of Cratoxylum formosum ssp. pruniflorum against nitric oxide (NO) was evaluated using RAW264.7 cells. Isolation of the CH2Cl2 extract of C. formosum ssp. pruniflorum roots afforded ten known xanthones including six tri-oxygenated xanthones (1-6) and four tetra-oxygenated xanthones (7-10), respectively. Compound 7 showed the highest inhibitory activity against NO release with an IC50 value of 3.9 μM, followed by compound 8 with an IC50 value of 4.3 μM, respectively. In order to understand the mechanism of this anti-inflammatory activity, the transcriptional level of 7 was found to down regulate mRNA expressions of iNOS and COX-2 in dose-dependent manners, whereas 8 inhibited only iNOS mRNA expression but did not affect on that of COX-2 gene. Xanthones might be the main anti-inflammatory components in C. formosum ssp. pruniflorum.

Diterpenoids and triterpenoids with potential anti-inflammatory activity from the leaves of Aglaia odorata

Chemical investigation of the leaves of the oriental medicinal plant Aglaia odorata resulted in the isolation of five compounds: two dolabellane diterpenoids, two dammarane triterpenoids and a protostane triterpenoid, along with twenty known compounds. Their structures were elucidated on the basis of extensive spectroscopic analysis and by comparison of their NMR spectroscopic data with those reported in the literature. The anti-inflammatory activities of all compounds were evaluated as inhibitory activities against lipopolysaccharide (LPS) induced nitric oxide (NO) production in RAW264.7 cell lines. Eleven compounds possessed potent nitric oxide inhibitory activity with IC(50) values ranging from 2.1 to 14.2 μM, these being better than that of the positive control, indomethacin (IC(50)=14.5 μM). In addition, three compounds exhibited significant activity against PGE(2) release with IC(50) values of 2.6, 16.1 and 23.0 μM.

Inhibitory effect of phenylbutanoid-rich Zingiber cassumunar extracts on nitric oxide production by murine macrophage-like RAW264.7 cells

Four phenylbutanoids, (E)-4-(3,4-dimethoxyphenyl)but-3-en-l-ol (I), (E)-4-(3,4-dimethoxyphenyl)but-3-en-l-yl acetate (II), (E)-1-(3,4-dimethoxyphenyl)butadiene (III) and (E)-3-(3,4-dimethoxyphenyl)-4-[(E)-3,4-dimethoxystyryl]cyclohex-1-ene (IV), isolated from Zingiber cassumunar, were used as standard markers for quantitative determination and preparation of phenylbutanoid-enriched Z. cassumunar extracts (PZEs). A reversed-phase HPLC method was established for the simultaneous determination of the phenylbutanoids in Z. cassumunar extracts. Systematic extraction studies to maximize phenylbutanoid content revealed that hexane was the most appropriate solvent for extraction. A one-step purification of the hexane crude extract of Z. cassumunar, using silica gel vacuum chromatography, provided the PZEs. The content of phenylbutanoids in the PZEs was up to 48.3% w/w dry weight. The anti-inflammatory activity of PZEs via inhibition of nitric oxide production by murine macrophage-like RAW264.7 cells was stronger than those of the four individual phenylbutanoids, the crude hexane extract and the essential oil of Z. cassumunar.

Analysis of biosynthetic fluctuations of cultured Taxus seedlings using a metabolomic approach

Fluctuations in the biosynthesis of taxoids in 1-5 year old cultured seedlings of Taxus chinensis var. mairei were investigated using LC-IT-TOF-MS and a metabolomics approach. In the total ion chromatogram (TIC) of the extracts, 16 prominent peaks were observed. Ten compounds were identified by comparison of retention times and MS/MS spectra with those of reference compounds. An additional 6 taxoids were isolated by preparative HPLC and identified by comparison of their spectroscopic data with those reported in the literature. It was clarified that the relative concentrations of taxoids with 4(20) double bonds are high at early stages of cultivation. On the other hand, relatively higher amounts of 5-acetoxy taxoids oxidized at the 4- and 10- positions and taxoids having 5(20)-oxetane rings were found at later stages of cultivation. This approach provides practical information on the biosynthetic flow of taxoids in cultured yew seedlings.

Cytochrome P450 3A4 inhibitory constituents of the wood of Taxus yunnanensis

From the aqueous extract of the wood of Taxus yunnanensis, which showed cytochrome P450 3A4 (CYP3A4) inhibition, a new isoflavan [(3S,4R)-4'-hydroxy-6,3'-dimethoxyisoflavan-4-ol (1)], a new degraded lignan [2,3-bis(hydroxymethyl)-7-hydroxy-6-methoxy-1-tetralone (2)], and a new lignan [(7R)-7-hydroxytaxiresinol (3)] were isolated, together with nine known lignans. Among the isolates obtained, α-conidendrin (12) showed strong CYP3A4 inhibition with an IC(50) value of 0.2 μM.

Anti-inflammatory principles of Suregada multiflora against nitric oxide and prostaglandin E2 releases

AIM OF THE STUDY

The stem bark of Suregada multiflora and the isolated compounds were carried out to investigate for anti-inflammatory activity.

MATERIALS AND METHODS

The stem bark of Suregada multiflora and its isolated compounds were tested for their anti-inflammatory effects against lipopolysaccharide (LPS)-induced nitric oxide (NO) and prostraglandin E(2) (PGE(2)) releases in RAW264.7 cells as well as the anti-inflammatory mechanism on mRNA expression of the active compound (5, helioscopinolide A).

RESULTS

The extract of Suregada multiflora possessed potent NO inhibitory effect with an IC(50) value of 8.6 μg/ml. Among the isolated compounds, helioscopinolide A (5) exhibited the highest activity against NO release with an IC(50) value of 9.1 μM, followed by helioscopinolide C (6) and suremulol D (2) with IC(50) values of 24.5 and 29.3 μM, respectively. The IC(50) value of 5 against PGE(2) production was found to be 46.3 μM. The mechanism in transcriptional level of compound 5 was found to inhibit iNOS and COX-2 mRNA expressions in dose-dependent manners.

CONCLUSIONS

The present study may support the traditional use of Suregada multiflora stem bark for treatment of inflammatory-related diseases.

Anti-inflammatory principles from Heritiera littoralis bark

Compounds from the hexane, dichloromethane and acetone extracts of Heritiera littoralis bark were investigated for their nitric oxide (NO) inhibitory effects using RAW264.7 macrophage cells. The result indicated that ergosterol peroxide (13) exhibited the highest activity against NO release with an IC(50) value of 2.5 microM, followed by 6-alpha-hydroxystigmast-4-en-3-one (11, IC(50)=9.5 microM) and stigmast-4-en-3-one (9, IC(50)=15.9 microM), whereas other compounds showed moderate and mild effects (25.4- > 100 microM). Ergosterol peroxide (13) and 6-alpha-hydroxystigmast-4-en-3-one (11) were also tested against prostaglandin E(2) (PGE(2)) and tumor necrosis factor alpha (TNF-alpha) releases. It was found that ergosterol peroxide (13) possessed marked activity against PGE(2) release with an IC(50) value of 28.7 microM, while 6-alpha-hydroxystigmast-4-en-3-one (11) was 86.7 microM. However, these two compounds were inactive towards TNF-alpha release (IC(50) > 100 microM). The mechanism in transcriptional level of ergosterol peroxide (13) was found to down regulate mRNA expressions of iNOS and COX-2 in dose-dependent manners.

Antioxidant Activity and Chemical Composition of Torreya grandis cv. Merrillii Seed

Torreya grandis cv. Merrillii is an endemic tree species in China, seeds of which are used as a popular snack, possessing beneficial effects on preventing angiosclerosis and coronary heart diseases. In this study, antioxidant activity and chemical constituents of T. grandis cv. Merrillii seed (TGMS) were investigated. The antioxidant activity of different fractions and the ethanol extract was evaluated using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity, hydroxyl radical scavenging activity and lipid peroxidation assays. The oil, CH2Cl2 and n-BuOH fractions, and ethanol extract of TGMS all showed antioxidant activities in these models, especially the DPPH one. By GC-MS analysis, twenty-seven constituents were identified from the oil fraction of TGMS. The total content of phenolic compounds in the CH2Cl2 and n-BuOH fractions and ethanol extract was also determined by the Folin-Ciocalteau method as 17.6, 21.6 and 12.9 μg/mg, respectively. In addition, analysis of the CH2Cl2 fraction yielded four phenolic compounds: 4-hydroxybenzaldehyde, 4-methoxy pyrocatechol, coniferyl aldehyde, 4-hydroxy cinnamaldehyde, and two steroids, β-sitosterol and daucosterol. These results provide scientific support for the empirical use of TGMS as a medicinal food for cardiovascular diseases.

Nitric oxide inhibitory principles from Derris trifoliata stems

Nine rotenoids were isolated from the hexane and dichloromethane extracts of Derris trifoliata stems and were tested for nitric oxide (NO) inhibitory activity using RAW264.7 cells. The result indicated that 12a-hydroxyrotenone (7) possessed very potent NO inhibitory activity with an IC(50) value of 0.002 microM, followed by 1 (deguelin, IC(50)=0.008 microM), 9 (12a-hydroxyelliptone, IC(50)=0.010 microM) and 2 (alpha-toxicarol, IC(50)=0.013 microM), respectively. In addition, the DPPH scavenging activity of rotenoids was also investigated. It was found that 6a,12a-dehydrodeguelin (5) possessed the highest activity against DPPH with an IC(50) value of 7.4 microM, followed by deguelin (1, IC(50)=27.4 microM). All compounds did not show any cytotoxicity at their IC(50) values for NO inhibitory activity. Structure-activity relationships (SARs) of these rotenoids against NO release are as follows: (1) hydroxylation at C12a dramatically increased activity, (2) prenylation at furan ring increased activity markedly and (3) hydrogenation of a double bond at C6a-C12a conferred higher activity. For the DPPH radical scavenging effect, it was found that (1) introduction of a double bond at C6a-C12a increased activity and (2) hydroxylation of C11 at the D-ring decreased activity. As regards active compounds of Derris trifoliata stems, the isolated compounds are responsible for the NO inhibitory effect, especially 7, 1, 9 and 2, whereas 5 and 1 are those for the DPPH scavenging activity.

Effects of rhinacanthins from Rhinacanthus nasutus on nitric oxide, prostaglandin E2 and tumor necrosis factor-alpha releases using RAW264.7 macrophage cells

Three naphthoquinone derivatives, rhinacanthin-C (1), -D (2) and -N (3) were isolated from the leaves of Rhinacanthus nasutus extract and were tested for anti-inflammatory activity. The result indicated that all three compounds possessed very potent anti-inflammatory activity against lipopolysaccharide (LPS)-induced nitric oxide release with IC(50) values of 1.8, 6.2 and 3.0 microM, respectively. In addition, the effects of rhinacanthin-C, -D and -N on LPS induced release of prostaglandin E(2) (PGE(2)) and tumor necrosis factor (TNF-alpha) were also examined. It was found that rhinacanthin-C exhibited the most potent on PGE(2) release with an IC(50) value of 10.4 microM, followed by rhinacanthin-D (IC(50)=14.4 microM) and rhinacanthin-N (IC(50)=52.1 microM), whereas those for TNF-alpha were inactive (IC(50)>100 microM). The mechanisms in transcriptional level of rhinacanthin-C were found to inhibit iNOS and COX-2 gene expressions in LPS-induced NO and PGE(2) releases from RAW264.7 cells in concentration-dependent manners. Regarding active constituents for anti-inflammatory activity of R. nasutus, rhinacanthins are responsible for this effect through the inhibition of NO and PGE(2) releases. The finding may support the traditional use of R. nasutus leaves for treatment of the inflammatory-related diseases.

Effects of compounds from Garcinia mangostana on inflammatory mediators in RAW264.7 macrophage cells

ETHNOPHARMACOLOGICAL RELEVANCE

The fruit hull of Garcinia mangostana Linn. has been used in Thai traditional medicine for treatment of abscess and skin infection.

AIM OF THE STUDY

The mangosteen fruit hull and its compounds were carried out to investigate for anti-inflammatory activity.

MATERIAL AND METHODS

The extract of Garcinia mangostana together with alpha- and gamma-mangostins were tested for anti-inflammatory effect against lipopolysaccharide (LPS)-induced nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor alpha (TNF-alpha) and interleukin-4 (IL-4) releases as well as their mechanisms in transcriptional levels using RAW264.7 macrophage cells.

RESULTS

Mangosteen extract possessed potent NO inhibitory effect with an IC50 value of 1.0 microg/ml. The isolated compounds from the extract including alpha-mangostin and gamma-mangostin, possessed marked inhibitory effect against NO release with IC50 values of 3.1 and 6.0 microM, respectively. The extract exhibited potent inhibitory effect on PGE2 release (IC50=6.0 microg/ml), whereas those of alpha- and gamma-mangostins were 13.9 and 13.5 microM, respectively. However, mangostins possessed only moderate effects towards TNF-alpha and IL-4 releases with IC50 values ranging from 31.8 to 64.8 microM. Both extract and alpha-mangostin suppressed transcription of gene encoding inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in dose-dependent manners, whereas gamma-mangostin had only an inhibitory effect on transcription of iNOS.

CONCLUSION

The present study may support the Thai traditional use of Garcinia mangostana fruit hull for treatment of inflammatory-related diseases through the inhibition of NO and PGE2 releases, but moderate effect through TNF-alpha and IL-4.

Effects of compounds from Kaempferia parviflora on nitric oxide, prostaglandin E2 and tumor necrosis factor-alpha productions in RAW264.7 macrophage cells

Kaempferia parviflora Wall. ex Baker, is one of the plants in the Zingiberaceae family, locally known in Thai as kra-chai-dam. The rhizome of this plant has been used for treatment of gout, apthous ulcer and abscesses. Since K. parviflora rhizomes have long been used for treatment of inflammation and possessed marked nitric oxide (NO) inhibitory activity (IC(50)=7.8microg/ml), we thus investigated the inhibitory activity of compounds isolated from this plant against lipopolysaccharide (LPS)-induced NO release in RAW264.7 cells. From bioassay-guided fractionation of K. parviflora, seven methoxyflavones were isolated from the hexane fraction and were tested for their anti-inflammatory effects. Among the isolated compounds, compound 5 (5-hydroxy-3,7,3',4'-tetramethoxyflavone) exhibited the highest activity against NO release with an IC(50) value of 16.1microM, followed by 4 (IC(50)=24.5microM) and 3 (IC(50)=30.6microM). Compound 5 was also tested on LPS-induced prostaglandin E(2) (PGE(2)) and tumor necrosis factor-alpha (TNF-alpha) releases from RAW264.7 cells. It was revealed that 5 showed appreciable inhibitory effect on PGE(2) release (IC(50)=16.3microM), but inactive on TNF-alpha (IC(50)>100microM). These findings may support the use in Thai traditional medicine of K. parviflora for treatment of inflammatory-related diseases through the inhibition of NO and PGE(2) releases but partly due to that of TNF-alpha.

Anticonvulsant, analgesic and antipyretic activities of Taxus wallichiana Zucc

Taxus wallichiana Zucc. (Himalayan Yew) is often used in northern areas of Pakistan for the treatment of pyrexia, acute pains and epilepsy. We have investigated certain pharmacological activities of the methanol leaf extract against convulsion, nociception and pyrexia induced in rodents. The aim was to justify and explore its folk uses in these pathological conditions, on scientific basis. The studies were carried out using acetic acid-induced nociception and pentylenetetrazole-induced convulsions in mice, while formalin test and yeast-induced pyrexia in rats. Significant analgesic (67.77 and 74.29%) effect was found in acetic acid-induced model at doses of 100 and 200mg/kg, i.p. respectively. Crude extract exhibited significant (P<0.05) inhibition of the formalin noxious stimulation on both early and late phases of pain by the extracts (100 and 200mg/kg doses). In case of yeast-induced pyrexia model, 200mg/kg dose showed very significant (P<0.01) inhibition while 50 and 100mg/kg dose caused a significant (P<0.05) inhibition. Plant extract has controlled the pentylenetetrazole-induced convulsions in mice. 100 and 200mg/kg i.p doses of the extract significantly (P<0.05) inhibited the mioclonus and clonus while inhibition of tonus and hind limb tonic extension (HLTE) was highly significant (P<0.01). The anticonvulsant activity of this plant has been reported for the first time throughout the whole genus. The observed pharmacological activities provide the scientific basis for the folkloric use of the plant in treating epilepsy, pyrexia and acute pain.

Nitric oxide inhibitory substances from the rhizomes of Dioscorea membranacea

Thai medicinal plants locally known as Hua-Khao-Yen were examined for their inhibitory activities against lipopolysaccharide (LPS) induced nitric oxide (NO) production in RAW 264.7 cell lines. Among the plant species studied, an ethanolic extract of Dioscorea membranacea exhibited the most potent inhibitory activity, with an IC(50) value of 23.6 microg/ml. From this extract, eight compounds [two naphthofuranoxepins (1, 2), one phenanthraquinone (3), three steroids (4-6) and two steroidal saponins (7, 8)] were isolated and further investigated for their inhibitory properties of NO production. It was found that diosgenin-3-O-alpha-L-rhamnosyl (1-->2)-beta-D-glucopyranoside (7) possessed the highest activity (IC(50)=3.5 microM), followed by dioscoreanone (3, IC(50)=9.8 microM) and dioscorealide B (2, IC(50)=24.9 microM). Regarding structural requirements of diosgenin derivatives for NO production inhibitory activity, compound 7 which has a rhamnoglucosyl moiety at C-3 exhibited much higher activity than compounds that have either a diglucosyl substitution (8) or its aglycone (9); whereas, hydroxyl substitution at position 8 of naphthofuranoxepin derivatives conferred higher activity than the methoxyl group. It is concluded that diosgenin-3-O-alpha-L-rhamnosyl (1-->2)-beta-D-glucopyranoside (7), dioscoreanone (3) and dioscorealide B (2) are active principles for NO inhibitory activity of Dioscorea membranacea. Compounds 1-3 were also tested for the inhibitory effect on LPS-induced TNF-alpha release in RAW 264.7 cells. The result revealed that 3 possessed potent activity against TNF-alpha release with an IC(50) value of 17.6 microM, whereas, 1 and 2 exhibited mild activity. The present study may support the use of Dioscorea membranacea by Thai traditional doctors for treatment of the inflammatory diseases.

In vivo anti-osteoporotic activity of isotaxiresinol, a lignan from wood of Taxus yunnanensis

Isotaxiresinol, the main lignan isolated from the water extract of wood of Taxus yunnanensis, was investigated for its effect on bone loss, on serum biochemical markers for bone remodeling and on uterine tissue, using ovariectomized (OVX) rats as the model of postmenopausal osteoporosis. After oral administration of isotaxiresinol (50 and 100mg/kg/d) for 6 weeks, bone mineral content (BMC) and bone mineral density (BMD) in total and cortical bones were increased as compared to those of OVX control rats, and decreases of three bone strength indexes induced by OVX surgery were prevented. Serum biochemical markers for bone remodeling revealed that isotaxiresinol slightly increased bone formation and significantly inhibited bone resorption without side effect on uterine tissue. These results suggest that isotaxiresinol may be useful for treatment of postmenopausal osteoporosis, especially for prevention of bone fracture induced by estrogen deficiency.

Hypoglycemic effects of the wood of Taxus yunnanensis on streptozotocin-induced diabetic rats and its active components

Hypoglycemic effects of the H(2)O and MeOH extracts of the wood of Taxus yunnanensis were examined in streptozotocin (STZ)-induced diabetic rats. The H(2)O extract significantly lowered the fasting blood glucose level by 33.7% at a 100mg/kg dose on intraperitoneal administration. From the active H(2)O extract of the wood, three lignans, i.e., isotaxiresinol (1), secoisolariciresinol (2) and taxiresinol (3), were isolated as major components. These lignans were further tested for their hypoglycemic effects on the same experimental model. At a dose of 100mg/kg (i.p.), isotaxiresinol (1) reduced the fasting blood glucose level of diabetic rats by 34.5%, while secoisolariciresinol (2) and taxiresinol (3) reduced by 33.4% and 20.9%, respectively. The blood glucose lowering effects of 1 and 2 were stronger than the mixture of tolbutamide (200mg/kg) and buformin (1mg/kg) used as a positive control, which lowered fasting blood glucose level by 24.0%.

Antiallergic Activity of Aqueous Extracts and Constituents of Taxus yunnanensis

The H2O, H2O/MeOH (1:1) extracts from the wood of Taxus yunnanensis showed a remarkable inhibitory effect on induced histamine release from the human basophilic cell line, KU812. The eleven constituents purified from the wood extracts of Taxus yunnanensis were tested by an in vitro histamine release inhibition assay. Among them, secoisolarciresinol and taxiresinol were found to show inhibitory activities. A new neolignan, 2-[2-hydroxy-5-(3-hydroxypropyl)-3-methoxyphenyl]-1-(4-hydroxy-3-methoxyphenyl)propane-1,3-diol, was isolated from the wood of Taxus yunnanensis.

Chemical studies on antioxidant mechanisms and free radical scavenging properties of lignans

The antioxidant activity, in terms of radical scavenging capacity, of altogether 15 different lignans was measured by monitoring the scavenging of the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). The effect of differences in skeletal arrangement or the degree of oxidation of the lignans was investigated in a structure-activity relationship study. A large variety in the radical scavenging capacities of the different lignans was observed and related to some structural features. Lignans with catechol (3,4-dihydroxyphenyl) moieties exhibited the highest radical scavenging capacity, while the corresponding guaiacyl (3-methoxy-4-hydroxyphenyl) lignans showed a slightly weaker scavenging capacity. In addition, the butanediol structure was found to enhance the activity, whereas a higher degree of oxidation at the benzylic positions decreased the activity. Additionally, the readily available lignans (-)-secoisolariciresinol, a mixture of hydroxymatairesinol epimers and (-)-matairesinol were studied in more detail, including kinetic measurements and identification of oxidation products in the reactions with DPPH and ABAP (2,2-azobis(2-methylpropionamidine) dihydrochloride. The identification of reaction products, by GC-MS, HPLC-MS and NMR spectroscopy, showed that dimerisation of the two aromatic moieties was the major radical termination reaction. Also, the formation of adducts was a predominant reaction in the experiments with ABAP. The kinetic data obtained from the reactions between the lignans and DPPH indicated a complex reaction mechanism.

Nitric Oxide (NO) Production Inhibitory Constituents of Tabebuia avellanedae from Brazil

From the water extract of Brazilian Tabebuia avellanedae, two new iridoids (1, 2) and a new phenylethanoid glycoside (3) have been isolated together with twelve known compounds (4-15). Their structures were determined based on the spectroscopic data. The isolated compounds inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-activated macrophage-like J774.1 cells. Compounds 1, 3, 10, 11, and 12 showed inhibitory activities more potent (IC50, 13.8-26.1 microg/ml) than a positive control N(G)-monomethyl-L-arginine (L-NMMA; IC50, 27.4 microg/ml).

Secoisolariciresinol and isotaxiresinol inhibit tumor necrosis factor-α-dependent hepatic apoptosis in mice

The effects of secoisolariciresinol (1) and isotaxiresinol (2), two major lignans isolated from the wood of Taxus yunnanensis, on tumor necrosis factor-alpha (TNF-alpha)-dependent hepatic apoptosis induced by D-galactosamine (d-GalN)/lipopolysaccharide (LPS) were investigated in mice. Co-administration of d-GalN (700 mg/kg) and LPS (10 microg/kg) resulted in a typical hepatic apoptosis characterized by DNA fragmentation and the formation of apoptotic bodies. Serum glutamic pyruvic transaminase (sGPT) and glutamic oxaloacetic transaminase (sGOT) levels were also raised at 8 h after d-GalN/LPS intoxication due to a severe necrosis of hepatocytes. Pre-administration of 1 or 2 (50, 10 mg/kg, i.p.) 12 and 1 h before d-GalN/LPS significantly reduced DNA fragmentation and prevented chromatin condensation, apoptotic body formation and hepatitis. Pro-inflammatory cytokines such as TNF-alpha and interferon-gamma (IFN-gamma) secreted from LPS-activated macrophages are important mediators of hepatocyte apoptosis in this model. Pre-treatment with 1 or 2 significantly inhibited the elevation of serum TNF-alpha and IFN-gamma levels. In a separate experiment, both lignans had a significant dose-dependent protective effect on d-GalN/TNF-alpha-induced cell death in primary cultured mouse hepatocytes and TNF-alpha-mediated cell death in murine L929 fibrosarcoma cells. These results indicated that 1 and 2 prevent d-GalN/LPS-induced hepatic injury by inhibiting hepatocyte apoptosis through the blocking of TNF-alpha and IFN-gamma production by activated macrophages and direct inhibition of the apoptosis induced by TNF-alpha.